1. Field of the Invention
The present invention relates to a fixing structure and a fixing method for fixing a semiconductor integrated circuit apparatus on a print wiring board while electrically connecting lead terminals of the semiconductor integrated circuit apparatus with pads of the print wiring board.
2. Description of Related Art
In a conventional method for mounting a semiconductor integrated circuit apparatus on a print wiring board, a socket having a plurality of electrical contact portions is prepared for a semiconductor integrated circuit apparatus, and each of a plurality of external connecting terminals of the semiconductor integrated circuit apparatus is connected with the corresponding electrical contact portion of the socket. Thereafter, the semiconductor integrated circuit apparatus is mounted on a print wiring board through the socket while being electrically connected with the print wiring board.
A conventional fixing structure for fixing the semiconductor integrated circuit apparatus on the print wiring board by using a conventional fixing method is described.
A cap is put on the semiconductor integrated circuit apparatus, which is mounted on the print wiring board, from the same direction as a mounting direction of the semiconductor integrated circuit apparatus, and four corners of the cap are screwed down so as to press the external connecting terminals of the semiconductor integrated circuit apparatus on the electrical contact portions of the socket. Therefore, the external connecting terminals of the semiconductor integrated circuit apparatus are tightly connected with the electrical contact portions of the socket, and the semiconductor integrated circuit apparatus is fixed on the print wiring board.
Also, in another conventional fixing structure using a conventional fixing method, after each external connecting terminal of the semiconductor integrated circuit apparatus is connected with the corresponding electrical contact portion of the socket, a cap is put on the semiconductor integrated circuit apparatus, and the cap and the semiconductor integrated circuit apparatus are pushed down toward the print wiring board in the same direction as a mounting direction of the semiconductor integrated circuit apparatus, while moving the cap by using a lever operated according to a cam mechanism, so as to press each external connecting terminal of the semiconductor integrated circuit apparatus on the corresponding electrical contact portion of the socket. Therefore, the external connecting terminals of the semiconductor integrated circuit apparatus are tightly connected with the electrical contact portions of the socket, and the semiconductor integrated circuit apparatus is fixed on the print wiring board.
However, because each external connecting terminal of the semiconductor integrated circuit apparatus is fixed on the print wiring board by using the conventional fixing structure for the semiconductor integrated circuit apparatus, the electrical contact portion of the socket is located between the external connecting terminal of the semiconductor integrated circuit apparatus and a wiring portion of the print wiring board. Therefore, a response time in the operation performed in the semiconductor integrated circuit apparatus is delayed by a contact capacitance of the electrical contact portion, and there is a problem that the performance of the semiconductor integrated circuit apparatus is adversely affected.
Also, in cases where the semiconductor integrated circuit apparatus is repeatedly used, the electrical contact portion of the socket may be deformed, or the cap may not be correctly fixed at a prescribed position. In this case, there is a problem that the external connecting terminal of the semiconductor integrated circuit apparatus is not connected with the electrical contact portion of the socket.
Also, the socket is soldered to the print wiring board to arrange the socket on the print wiring board. Therefore, in cases where the electrical contact portion of the socket is deformed, there is a problem that it is difficult to replace the socket with a new socket when the electrical contact portion of the socket is deformed.
Also, because the number of socket terminals respectively soldered to the print wiring board corresponds to the number of external connecting terminals of the semiconductor integrated circuit apparatus, it is required to perform the soldering of the socket terminal to the print wiring board many times. Therefore, there is a problem that it takes a lot of time to connect the socket with the print wiring board.
Also, because the number of external connecting terminals of a semiconductor integrated circuit apparatus and the shape of the external connecting terminals depend on a type of the semiconductor integrated circuit apparatus, various types of sockets respectively matching with one type of semiconductor integrated circuit apparatus are required. Therefore, there is a problem that the fixing structure cannot be prepared at a low cost.
An object of the present invention is to provide, with due consideration to the drawbacks of the conventional fixing structure and the conventional fixing method for the semiconductor integrated circuit apparatus, a fixing structure and a fixing method for a semiconductor integrated circuit apparatus in which the semiconductor integrated circuit apparatus is easily and reliably fixed on a print wiring board at a low cost, without delaying a response time in the operation of the semiconductor integrated circuit apparatus, while electrically connecting the semiconductor integrated circuit apparatus with the print wiring board.
The object is achieved by the provision of a fixing structure for a semiconductor integrated circuit apparatus, in which a semiconductor integrated circuit apparatus is fixed on a print wiring board, comprising:
a hole portion arranged in the print wiring board; and
suction and fixing means for suctioning the semiconductor integrated circuit apparatus through the hole portion to press an external connecting terminal of the semiconductor integrated circuit apparatus on a wiring portion of the print wiring board and fixing the semiconductor integrated circuit apparatus on the print wiring board.
Also, the object is achieved by the provision of a fixing method for a semiconductor integrated circuit apparatus, comprising the steps of:
preparing a hole portion arranged in a print wiring board;
suctioning a semiconductor integrated circuit apparatus through the hole portion so as to press an external connecting terminal of the semiconductor integrated circuit apparatus on a wiring portion of the print wiring board; and
fixing the semiconductor integrated circuit apparatus on the print wiring board.
In the above configuration and steps, because the suction and fixing means suctions the semiconductor integrated circuit apparatus through the hole portion, the semiconductor integrated circuit apparatus is drawn toward the print wiring board. Therefore, the external connecting terminal of the semiconductor integrated circuit apparatus is pressed on the wiring portion of the print wiring board by suction.
Accordingly, the semiconductor integrated circuit apparatus can be easily and reliably fixed on the print wiring board at a low cost regardless of a type of the semiconductor integrated circuit apparatus.
Also, because no electrical contact portion exists between the external connecting terminal of the semiconductor integrated circuit apparatus and the wiring portion of the print wiring board, there is no probability that a response time in the operation of the semiconductor integrated circuit apparatus is delayed by a contact capacitance of an electrical contact portion.
Also, because no electrical contact portion is used in the fixing structure, the fixing structure can be simplified. Therefore, the fixing structure can be easily manufactured. Also, even though the semiconductor integrated circuit apparatus is fixed on the print wiring board many times, there is no probability that the semiconductor integrated circuit apparatus receives mechanical damage.
Also, because the external connecting terminal of the semiconductor integrated circuit apparatus is pressed on the wiring portion of the print wiring board by suction, the semiconductor integrated circuit apparatus can be electrically connected with the print wiring board without a soldering operation. Therefore, a time required to fix the semiconductor integrated circuit apparatus on the print wiring board can be reduced.
Also, the fixing structure is useful regardless of whether a surface mounting type semiconductor integrated circuit apparatus has a plurality of external connecting terminals on both sides or on all four sides. Also, the fixing structure is useful regardless of the number of external connecting terminals, the pitch of the external connecting terminals or a size of a package in which the external connecting terminals is accommodated. Therefore, the fixing structure can be widely used.
Also, no cap covering the semiconductor integrated circuit apparatus is used to fix the semiconductor integrated circuit apparatus on the print wiring board, an exposed area of the semiconductor integrated circuit apparatus is sufficient to radiate heat from the semiconductor integrated circuit apparatus. Therefore, the heat radiation of the semiconductor integrated circuit apparatus can be improved, and the performance of the semiconductor integrated circuit apparatus can be reliably maintained even though a degree of heat generated in the semiconductor integrated circuit apparatus is high.
It is preferred that the suction and fixing means comprises a suction portion for suctioning the semiconductor integrated circuit apparatus through the hole portion; a fixing portion for making contact with the print wiring board in the suctioning of the suction portion; and a pressure reducing tube portion, connected with an external pressure reducing unit, for setting the suction portion to a pressure reduced state.
In the above configuration, because the suction portion is set to a pressure reduced state by reducing an internal, pressure of the suction portion by the operation of the external pressure reducing unit, the suction portion can suction the semiconductor integrated circuit apparatus. Also, because the fixing portion makes contact with the print wiring board, the suction and fixing means can be positioned into the hole portion arranged in the print wiring board.
It is preferred that the suction portion, the fixing portion and the pressure reducing tube portion are integrally formed with each other.
Therefore, the mass production of the suction and fixing means can be improved.
It is preferred that the suction and fixing means comprises a plurality of suction portions for respectively suctioning the semiconductor integrated circuit apparatus through the hole portion; a fixing portion for making contact with the print wiring board in the suctioning of the suction portions; and a pressure reducing tube portion, connected with an external pressure reducing unit, for setting each of the suction portions to a pressure reduced state.
In the above configuration, because the plurality of suction portions respectively suction the semiconductor integrated circuit apparatus, even though the size of the semiconductor integrated circuit apparatus is sufficiently large as compared with a total area of the suction portions, the semiconductor integrated circuit apparatus can be uniformly drawn toward the print wiring board by the suction portions without inclining the semiconductor integrated circuit apparatus with respect to the print wiring board. Therefore, the semiconductor integrated circuit apparatus can be stably fixed on the print wiring board while precisely positioning the external connecting terminal of the semiconductor integrated circuit apparatus on the pad of the print wiring board.
It is preferred that the fixing portion of the suction and fixing means is pressed into the hole portion of the print wiring board to fix the suction and fixing means to the print wiring board.
Because the suction and fixing means is fixed to the print wiring board by pressing the fixing portion into the hole portion, the configuration of the suction and fixing means can be simplified, and the semiconductor integrated circuit apparatus can be fixed on the print wiring board without the semiconductor integrated circuit apparatus being out of position.
It is preferred that the fixing portion of the suction and fixing means is soldered to a reverse surface of the print wiring board to fix the suction and fixing means to the print wiring board.
Therefore, the suction and fixing means can be reliably fixed to the print wiring board, and the semiconductor integrated circuit apparatus can be fixed on the-print wiring board without the semiconductor integrated circuit apparatus being out of position.
It is preferred that the suction and fixing means adjusts a degree of pressure of the external connecting terminal of the semiconductor integrated circuit apparatus, which is applied on the wiring portion of the print wiring board, according to the pressure reduced state of the suction portion.
Therefore, there is no probability that the external connecting terminal of the semiconductor integrated circuit apparatus is excessively pressed on the wiring portion of the print wiring board, and the external connecting terminal of the semiconductor integrated circuit apparatus can be prevented from being mechanically damaged.
It is preferred that the suction and fixing means adjusts a degree of pressure of the external connecting terminal of the semiconductor integrated circuit apparatus, which is applied on the wiring portion of the print wiring board, by moving the suction and fixing means in a suction direction.
Therefore, the electrical connection between the external connecting terminal of the semiconductor integrated circuit apparatus and the wiring portion of the print wiring board can be reliably obtained.
It is preferred that the fixing structure further comprises a positioning guide, arranged on the print wiring board, for positioning the semiconductor integrated circuit apparatus.
In the above configuration, the operation for positioning the semiconductor integrated circuit apparatus on the print wiring board can be simplified, and the fixing of the semiconductor integrated circuit apparatus on the print wiring board can be easily performed.
It is preferred that the wiring portion is placed in a xe2x80x98concave area of the print wiring board, and the external connecting terminal of the semiconductor integrated circuit apparatus is pressed on the wiring portion placed in the concave area of the print wiring board.
Therefore, the external connecting terminal of the semiconductor integrated circuit apparatus can be easily put on the wiring portion of the print wiring board, and the external connecting terminal of the semiconductor integrated circuit apparatus-can be-reliably pressed on the wiring portion of the print wiring board without the external connecting terminal being out of position.
It is preferred that the wiring portion is placed in a convex area of the print wiring board, and the external connecting terminal of the semiconductor integrated circuit apparatus is pressed on the wiring portion placed in the convex area of the print wiring board.
Therefore, because the wiring portion is placed in the convex area of the print wiring board, an operator can easily ascertain the position of the wiring portion in three dimensions, and the external connecting terminal of the semiconductor integrated circuit apparatus can be easily put on the wiring portion of the print wiring board. Also, because the convex area of the print wiring board can be easily deformed, a degree of pressure of the external connecting terminal of the semiconductor integrated circuit apparatus, which is applied on the wiring portion of the print wiring board, can be heightened, and the electrical connection between the external connecting terminal of the semiconductor integrated circuit apparatus and the wiring portion of the print wiring board can be reliably obtained.
It is preferred that the fixing structure further comprises a guide layer which has a concave area and is arranged on the print wiring board, and the wiring portion of the print wiring board is placed in the concave area of the guide layer.
In the above configuration, the setting position of the external connecting terminal of the semiconductor integrated circuit apparatus can be easily determined, and the external connecting terminal of the semiconductor integrated circuit apparatus can be reliably pressed on the wiring portion of the print wiring board without the external connecting terminal being out of position.
It is preferred that the suction and fixing means is formed of elastic material.
Because the suction and fixing means is deformed to reduce a size of the suction and fixing means, a force of restitution is generated in the suction and fixing means, and the external connecting terminal of the semiconductor integrated circuit apparatus is strongly pressed on the wiring portion of the print wiring board.